Amazon has the Western Digital 640 GB 5400rpm SATA2 8 MB 2.5-Inch Notebook
Hard Drive WD6400BEVT (Scorpio Blue): http://www.amazon.com/Western-Digital-2-5-Inch-Notebook-WD6400B
for $59.99
I had a camelcamelcamel alert set up so I just saw that this HD is down from
$69.99 recently. Unless you can get a deal through WD's Loyalty Program
this is the best price for this drive in the last 2.5 months or so.
Cheers.